Couplers are known for securing construction attachments such as buckets, impact hammers, shears, etc. fixedly and operatively to the distal end of an arm of a tractor, backhoe, excavator or other type of arm-equipped construction/agricultural equipment (any such tractor, backhoe, excavator or the like is referred to herein as an “excavator”). As is generally known, these couplers, also referred to as “quick couplers,” are used as an alternative to a pin-on connection for fixedly and operatively securing an associated attachment to the distal end of an arm which is, in turn, secured to a boom of a construction/agricultural machine such as a backhoe or other excavator. Over the years, the safety of such couplers has been greatly improved with respect to minimizing the chance for equipment failure and/or operator error leading to accidental decoupling of the associated attachment, and the present development is directed to a coupler with new and improved safety features.